MerR Cross-Links to the α, β, and σ70 Subunits of RNA Polymerase in the Preinitiation Complex at the merTPCAD Promoter
- 26 February 1999
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 38 (11) , 3362-3368
- https://doi.org/10.1021/bi982814m
Abstract
MerR, the metalloregulator of the mercury resistance (mer) operon, binds the operator (merO) between −10 and −35 of the merTPCAD promoter (PT) and sequesters RNA polymerase (RNAP) in a closed complex. MerR represses PT until Hg(II) induces it to underwind merO DNA and thus facilitate open complex formation. We used cross-linking to determine if direct contacts between MerR and RNAP also occur during this process. MerR cross-linked to the α, β, and σ70 subunits of RNAP alone, indicating stable contacts which were further stabilized upon forming the preinitiation complex at PT. Hg(II) did not eliminate any of the MerR−RNAP cross-links but did increase the relative abundance of a MerR dimer conformer. Interference by MerR with self-cross-links among RNAP subunits and the formation of an electrophoretically stable association between MerR and RNAP also indicated MerR−RNAP interactions. This is the first evidence for stable physical contacts between MerR and RNAP and for a Hg(II)-induced allosteric change in MerR in the transcription-competent complex.Keywords
This publication has 15 references indexed in Scilit:
- Ada Protein-RNA Polymerase ς Subunit Interaction and α Subunit-Promoter DNA Interaction Are Necessary at Different Steps in Transcription Initiation at the Escherichia coli adaandaidBPromotersPublished by Elsevier ,1998
- Molecular anatomy of a transcription activation patch: FIS-RNA polymerase interactions at the Escherichia coli rrnB P1 promoterThe EMBO Journal, 1997
- Transcription Activation by the Bacteriophage Mu Mor Protein Requires the C-terminal Regions of Both α and σ70 Subunits of Escherichia coli RNA PolymerasePublished by Elsevier ,1996
- Identification of the Target of a Transcription Activator Protein by Protein-Protein PhotocrosslinkingScience, 1994
- Amino acid substitutions in the -35 recognition motif of sigma 70 that result in defects in phage lambda repressor-stimulated transcriptionJournal of Bacteriology, 1994
- Repression versus activation in the control of gene transcriptionTrends in Biochemical Sciences, 1994
- Catalytic Activity of an RNA Domain Derived from the U6-U4 RNA ComplexScience, 1994
- A mer-lux transcriptional fusion for real-time examination of in vivo gene expression kinetics and promoter response to altered superhelicityJournal of Bacteriology, 1992
- Homologous metalloregulatory proteins from both gram-positive and gram-negative bacteria control transcription of mercury resistance operonsJournal of Bacteriology, 1989
- Overexpression and DNA-binding properties of the mer-encoded regulatory protein from plasmid NR1 (Tn21)Journal of Bacteriology, 1987